The present invention relates generally to the H. 323 standard for transmitting audio and video data streams, and more particularly to extending the H.323 standard to support mobility in a multimedia communication system with services over packet-based networks.
Originally, the International Telecommunications Union (ITU) developed H.323 as an adaptation of H.320, which addresses videoconferencing over ISDN and other circuit-switched networks and services. H.320 was ratified in 1990, and corporations expanded their networks to include Local Area Networks (LANs) and LAN gateways to the Wide Area Network (WAN). Then, H.323 was expanded beyond being an extension of H.320 so that H.323 now covers the corporate intranets and packet-switched networks in general. The ITU published a set of standards for multimedia communication over packet-based networks (PBNs) under the H.323 designation, which includes standards for data channels, monitoring channels, and control channels. It includes provision of real-time audio, video and/or data communications. The H.323 components defined by the standard include: terminals, gateways, gatekeepers and multipoint control units (MCUs). The terminals provide real-time communications, must support audio/voice communications and optionally support data and video. The most common H.323 terminals are the applications that run on a personal computer (PC). H.323 gateways provide services to H.323 clients and allow communication with non-H.323 entities, such as communication between H.323 terminals and telephone in a circuit-switched network. Gatekeepers provide call control services for H.323 endpoints, e.g., address translation and bandwidth management. Gatekeepers are optional in the H.323 standard, but, if they are present, the endpoints must use the services of the gatekeepers. The H.323 standard specifies certain mandatory services that gatekeepers, if utilized, must provide. The multipoint control units provide support for conferences of three or more endpoints by managing conference resources, manage negotiations between the endpoints to specify which audio or video codec(s) to use and may manage the media stream. The H.323 standard defines how audio and video conferencing systems communicate over packet-switched networks defines call control and management practices for point-to-point and broadcast/multicast/unicast multipoint conferences, addresses QoS issues with a centralized gatekeeper that LAN administrators use to manage media traffic, bandwidth and user participation, and describes functionality that allows calls to connect from the LAN to the Public Switched Telephone Network (PST) as well as to other H.32x standards-based terminals.
In version 2 of the H.323 standard, video and audio data streams are compressed and packetized in accordance with a real-time transport protocol (RTP/RTCP) standard from the Internet Engineering Task Force (IETF) and are used to support video conferencing and other communications over the Internet. Packets include data and header information which facilitates detection of packet loss, detection of packet status and synchronization of the packets. The video data streams may use H.261, H.262, or H.263 protocols. Audio data streams may use G.711, G.722, G.723.1 G.728 or G.729 protocols. Generally, the H.323 standard supports teleconferencing in networks that utilize TCP/IP, such as, for example, the Internet.
The H.323 system supports interoperability and assumes that users, terminals, and services are fixed. If an H.323 terminal is moved form one network to another, its point of attachment or network address changes. In this situation, the address of the mobile terminal needs to be resolved to set up a new call or continue a same call. Thus, there is a need for an H.323 mobility architecture that provides for terminal, user and service mobility.
The present invention provides an intelligent signaling scheme for a computer-based medium for an H.323-based mobility architecture for real-time mobile multimedia communications and conferencing over packet-based networks wherein a plurality of H.323 mobility gatekeepers provide notification of H.323 mobility services availability by periodically multicast, broadcasting, and/or unicast a Mobility Gatekeeper Advertisement with a multicast/unicast address as appropriate. If needed, the mobile Terminal/Node/Entity can also multicast, broadcast, and/or unicast a discovery message seeking a gatekeeper that provides the mobility services. The protocol includes the steps of detecting, by a Mobile Terminal/Node/Entity, whether it has changed its location in a given zone or domain where zone and (administrative) domain have been defined in accordance to ITU-T Recommendations H.323 and H.225.0. The abstraction of zone is such that it is managed by a gatekeeper while a domain consists of one or more zones. A domain may be administered by an administration (e.g., an Internet Service Provider (ISP), a corporation, a carrier network, etc.). The communications between the domains are via border elements (BEs). However, the border elements can communicate with the gatekeeper.
The invention provides a computer-readable medium having computer-executable steps for implementing, by a Mobile Terminal/Node/Entity, an H.323-based mobility protocol for real-time mobile multimedia communications and conferencing over packet-based networks wherein a plurality of H.323 mobility gatekeepers provide notification of H.323 mobility services availability by periodically broadcasting/multicasting/unicasting a Mobility Gatekeeper Advertisement with a multicast address. The computer-executable steps typically include: where the Mobile Terminal/Node/Entity becomes mobile and initiates an H.323 communication that includes at least one of: audio, video and data, by the Mobile Terminal, Node or Entity, with respect to notification, one of providing, by at least one of a plurality of available H.323 Home/Foreign Mobility Gatekeepers, notification of H.323 mobility services availability by periodically broadcasting/multicasting/unicasting a Mobility Gatekeeper Advertisement with a multicast/unicast address; and the Mobile Terminal/Node/Entity lacks notification of H.323 mobility services availability, broadcasting, multicasting, unicasting or sending, by the Mobile Terminal, Node or Entity, a message to the Home Gatekeeper/Home Location Database, which notifies H.323 Home/Foreign Mobility Gatekeepers in a preselected area local to the Mobile Terminal/Node/Entity that the Mobile TerminaVNode/Entity needs H.323 mobility services and notifying, by the H.323 Home/Foreign Mobility Gatekeepers, the Mobile Terminal/Node/Entity of available H.323 Home/Foreign Mobility Gatekeepers; registering, by the Mobile Terminal/Node/Entity, with a H.323 Home/Foreign Mobility Gatekeeper of the available H.323 Home/Foreign Mobility Gatekeepers that support H.323 mobility services in a Location Area/Cell/Zone of the Mobile Terminal/Node/Entity; and providing, for the Mobile Terminal/Node/Entity by the H.323 Home/Foreign Mobility Gatekeeper with which the Mobile Terminal/Node/Entity is registered, support for the H.323 communication that includes at least one of: audio, video and data.
Registering with the H.323 Home/Foreign Mobility Gatekeeper may include sending registration information for the Mobile Terminal/Node/Entity using a Base Station to Base Station Controller to Mobile Switching Center to H.323 Home/Foreign Gatekeeper system in the case of the cellular wireless networking environment. In wireless/wire-line LAN/wire-line environment, the H.323 mobile entity can register with the H.323 Home/Foreign Mobility GK via the wireless/wire-line LAN/wire-line where the GK may be connected to the packet network including the wireless/wire-line network. Registering with the at least one H.323 Home/Foreign Mobility Gatekeeper may include sending registration information for the Mobile Terminal/Node/Entity using a wireless/wire-line Local Area Network to Router/Switch to H.323 Home/Foreign Gatekeeper system. Where desired, registering may include the steps of: broadcasting, multicasting, unicasting or sending, by the Home Gatekeeper, a Mobility Gatekeeper Advertisement (MGA) message periodically; broadcasting, multicasting, unicasting or sending a registration request message (RRQ) to the Home Gatekeeper by the Mobile Terminal/Node/Entity; and sending, by the Home Gatekeeper, a registration confirmation/registration rejection (RCF/RRJ) to the Mobile Terminal/Node/Entity.
Registering may also include the steps of: upon determining, by the Mobile Terminal, Node or Entity, that a network point of attachment has changed/a foreign zone has been entered, broadcasting, multicasting, unicasting or sending, by the Mobile Terminal, Node or Entity, a registration request message (RRQ) to a Foreign/Visiting Gatekeeper; broadcasting, multicasting, unicasting or sending, by the Foreign/Visiting Gatekeeper, a binding update message (BuRQ) to the Home Gatekeeper; broadcasting, multicasting, unicasting or sending, by the Home Gatekeeper, a binding update confirmation or rejection (BuCF/BuRJ) to the Foreign/Visiting Gatekeeper; broadcasting, multicasting, unicasting or sending, by the Foreign/Visiting Gatekeeper, the binding update confirmation/rejection to the Mobile Terminal or Node/Entity.
Where the Mobile Terminal/Node/Entity has already visited another foreign zone regulated by a Visited Gatekeeper, registering may include: broadcasting, multicasting, unicasting or sending, by the Home Gatekeeper, a mobility unbinding message (UbRQ) to the Visited Gatekeeper; and broadcasting, multicasting, unicasting or sending, by the Visited Gatekeeper, a mobility unbinding confirmation/rejection (UbCF/UbRJ) to the Home Gatekeeper. Where the Mobile Terminal/Node/Entity has already visited another foreign zone regulated by a Visited Gatekeeper, registering may include: broadcasting, multicasting, unicasting or sending, by the Mobile Terminal/Node/Entity, a registration request message (RRQ) to a Foreign/Visiting Gatekeeper; broadcasting, multicasting, unicasting or sending, by the Foreign/Visiting Gatekeeper, a mobility unbinding update message (UbRQ) to the Visited Gatekeeper; broadcasting, multicasting, unicasting or sending, by the Visited Gatekeeper, a mobility unbinding confirmation/rejection (UbCF/UbRJ) to the Foreign/Visiting Gatekeeper; broadcasting, multicasting, unicasting or sending, by the Foreign/Visiting Gatekeeper, a provisional registration confirmation to the Mobile Terminal, Node, or Terminal and broadcasting, multicasting, unicasting or sending, by the Foreign/Visiting Gatekeeper, a binding update message (BuRQ) to the Home Gatekeeper; and broadcasting, multicasting, unicasting or sending, by the Home Gatekeeper, a binding update confirmation or rejection (BuCF/BuRJ) to the Foreign/Visiting Gatekeeper.
Where the Mobile Terminal/Node/Entity has already visited another foreign zone regulated by a Visited Gatekeeper, registering may include: broadcasting, multicasting, unicasting or sending, by the Mobile Terminal, Node or Entity, a registration request message (RRQ) to a Foreign/Visiting Gatekeeper; broadcasting, multicasting, unicasting or sending, by the Visited Gatekeeper, a mobility unbinding confirmation or rejection (UbCF/UbRJ) to the Foreign/Visiting Gatekeeper; broadcasting, multicasting, unicasting or sending, by the Foreign/Visiting Gatekeeper, a provisional registration confirmation to the Mobile Terminal or Node/Terminal and broadcasting, multicasting, unicasting or sending, by the Foreign/Visiting Gatekeeper, a binding update message (BuRQ) to the Home Gatekeeper; broadcasting, multicasting, unicasting or sending, by the Home Gatekeeper, a binding update confirmation or rejection (BuCF/BuRJ) to the Foreign/Visiting Gatekeeper; broadcasting, multicasting, unicasting or sending, by the Home Gatekeeper, a mobility unbinding update message (UbRQ) to the Visited Gatekeeper; and broadcasting, multicasting, unicasting or sending, by the Visited Gatekeeper, a mobility unbinding confirmation/rejection (UbCF/UbRJ) to the Home Gatekeeper.
Where desired, at least one Home or Foreign Gatekeeper may utilize a combined Home/Visitor Location Database. Also, where desired, a plurality of Home/Foreign Gatekeepers may each utilize an individual Visitor Location Database and share a Home Location Database.
Where the Mobile Terminal/Node/Entity is originally located in a First Administrative Domain and is moving in a Second Administrative Domain, registering may include: broadcasting, multicasting, unicasting or sending a registration request message (RRQ), by the Mobile Terminal/Node/Entity to the Foreign/Visiting Gatekeeper; broadcasting, multicasting, unicasting or sending, by the Foreign/Visiting Gatekeeper, a mobility unbinding (UbRQ) message to a Visited Gatekeeper; broadcasting, multicasting, unicasting or sending, by the Visited Gatekeeper, an unbinding confirmation or rejection (UbCF/UbRJ) to the Visiting/Foreign Gatekeeper; broadcasting, multicasting, unicasting or sending, by the Visiting Gatekeeper, a provisional registration message to the Mobile Terminal/Node/Entity; broadcasting, multicasting, unicasting or sending, by the Foreign/Visiting Gatekeeper, a mobility binding message (BuRQ) to a Border Element of the Second Administrative Domain, which forwards the message to a Border Element of the First Administrative Domain which then forwards the message to the Home Gatekeeper; broadcasting, multicasting, unicasting or sending, by the Home Gatekeeper, a mobility binding confirmation or rejection (BuCF/BuRJ) message to the Border Element of the First Administrative Domain, which forwards the message to the Border Element of the Second Administrative Domain, which forwards the message to the Visiting Gatekeeper.